Heat exchanger bundle



June 13, 1967 R MlLLER 3,324,942

HEAT EXCHANGER BUNDLE Filed April 12, 1965 5 Sheets-Sheet 1 INVENTOR.

June 13, 1967 H. R. MILLER 3,324,942

HEAT EXCHANGER BUNDLE Filed April 12, 1965 5 Sheets-Sheet 2 74 K INVENTOR.

June 13, 1967 M L 3,324,942

HEAT EXCHANGER BUNDLE Filed April 12 1965 5 Sheets-Sheet 3 INVENTOR.

June 13, 1967 H. R. MILLER 3,324,942

HEAT EXCHANGER BUNDLE Filed April 12, 1965 INVENTOR ,ZjWK-M 5 Sheets-Sheet 4 June 13, 1967 H. R. MJLLER 3,324,942

HEAT EXCHANGER BUNDLE Filed April 12, 1965 5 Sheets-$heet 5 I N VEN TOR.

United States Patent M 3,324,942 HEAT EXCHANGER BUNDLE Harvey Richard Miller, R0. Box 2334, Maplewood', La. 70663 Filed Apr. 12, 1965, Ser. No. 447,181 11 Claims. (Cl. 165-173) My invention relates to tubular heat exchanger bundles particularly of the Floating Head and U bend types which do not have the tubes permanently fixed to the tube sheet but instead are removable for individual cleaning and reinstallable in the bundle When the complete bundle is out of the exchanger shell or casing.

The object of my invention is to provide a breakdown tube clamping and tube positioning baffle assembly that will allow a new and different method of lifting a number of tubes at a time from the baflles when the bundle is being disassembled for individual tube cleaning and the tubes laid back in the baflles when the bundle is being reassembled. This eliminates the present time consuming method of pulling the tubes one at a time through the holes in the tubesheet and baffles and replacing them through the close fitting holes in the tubesheets and intervening bafiies. This will also eliminate the costly manufacture and use of tube retainer plates that are attached to the outside faces of the tubesheets to prevent the tubes from moving out of the tubesheets and O-ring fluid pressure seals by forces produced by differential fluid pres sure. The slightest chance of the tubes moving from the tubesheets and O-ring seals will not and cannot be tolerated by the refining and chemical industries where contamination would result between the fluid on the tube side and the fluid on the shell side of the heat exchanger.

Another object is to provide the tubesheet in the exchanger bundle with O-ring cavity as a circular groove in the tube hole wall that completely confines any suitable O-ring fluid pressure seal element around the tube extending through the tubesheet so that the tubesheet and the O-ring seal element can be removed and reinstalled as an assembly when the bundle is disassembled and reassembled. This will eliminate the unavoidable removal of each O-ring seal element and damages to many when the bundle is disassembled and the individual installation of each O-ring element and damage to many when the bundle is reassembled. This will also eliminate the necessity of the plates on the outside faces of the tubesheets to retain the O-ring seal elements in the O-ring caviy existing as a counterbore from the outside face of the tubesheet.

Another object is to provide a structure whereby O-ring fluid pressure seals can be used in U bend type heat exchanger bundles. This cannot be accomplished by prior art structure where the mechanical principle of an elastic and resilient O-ring fluid pressure seal is used in the tubesheet and around the tube extending therethrough to seal against the m'ming of the fluids on the tube and shell sides of the exchanger unit.

The more recently devised prior art heat exchanger bundles using elastic and resilient O-ring seal elements to seal between the outer surface of the tube and the wall of the hole in the tubesheet through which the tube extend, consists essentially of a tubesheet at each end of the bundle that have counterbores from the outside faces of the tubesheets to act as O-ring cavities and a tube retainer plate attached to the outside faces of the tubesheets. These tube retainer plates are also counterbored to receive the end of the tube and the bottom of the counterbore acts as an abutment for the end of the tube at each end of the bundle to retain it from moving longitudinally from the tubesheet. This retainer plate is also necessary to retain the O-ring in the counterbored O-ring 3,324,942 Patented June 13, 1967 cavity. This structure can only be adapted to floating head and fixed tubesheet type heat exchanger units where they have the tube retainer plates on the tubesheets at each end of the bundle. This type structure cannot be adapted to a U bend type bundle where there is only one tubesheet because the preponderance of the fluid pressure when on the tube side will force the tube out of the tubesheet in the direction towards the shell side of the exchanger unit.

The conventional type bundles are equipped with baflle plates in the form of circular segments normally having 600 to 800 close fitting holes in each baflle through which the tubes extend from one tube sheet to the other. There are as many as 30 baflles alternately spaced throughout the length of some bundles but it is more common to have from 8 to 10 baflles. The tubes must be pulled for cleaning one at time through the holes in one tubesheet and all the baflles. The O-ring seal elements are unavoidably removed and many damaged by special tools used to apply force to drive the tubes from the tubesheet at one end of the bundle. The O-ring seal elements in the tubesheet at the other end of the bundle ride the tube out of the counterbore at that end. In many instances there is a very hard material on the external surfaces of the tubes and considerable force is required by mechanical tuggers with tube attaching means to shear this material off where tubes pass through the close fitting holes in the baflles and tubesheet. In many services this desirable type breakdown bundle cannot be used because the material is too hard to be sheared from the outside surface of the tubes.

The tubes are then cleaned and reinstalled in the bundle by one person pushing the tubes one at a time through the hole in the tubesheet at one end of the bundle and one person guiding the tube end through the holes in each battle and into the hole of the tubesheet at the opposite end of the bundle. This requires one man walking back and forth the sixteen to twenty foot lengths of bundles each time a tube is installed. The O-ring seal elements are reinstalled one at a time into the counterbore O-ring cavities and around the tubes by the use of a special tool. Many are damaged in this operation. The tube retainer plates are reinstalled on the outside faces of each tubesheet. Thus, the labor involved is very time consuming when there are 1000 to 1400 sixteen to twenty foot long tubes in a conventional bundle and two tubesheets in which O-ring elements must be installed. There are many refining and chemical industries who have 3 to 4 hundred of this size bundles in their plants. Many require cleaning every 60 to days and the cleaning cost is as high as $1,000 per bundle.

The features of my novel structure makes it poss ble to lift a plurality of tubes from the bundle at one time when the bundle is disassembled and replace them at one time when the bundle is reassembled. It completely eliminates pulling the tubes through the tubesheet and baflies, installing the O-ring elements one at a time in each tubesheet and installing the tube retainer plates on each of the two tubesheets. My O-rings do not have to be removed or reinstalled one at a time when the bundle is disassembled and reassembled. A substantial savings in time and labor is thereby effected considering there are as many as 1400 tubes and 2800 O-ring elements in a bundle. Damage to the O-ring is also avoided when the tubes are removed and reinstalled at each cleaning. Damaged O-rings result in leaks so that time consuming repairs after the bundle is assembled, will also be avoided.

No special tools are required to install the O-rings element in my structure. They are easily and rapidly installed in the O-ring cavities by the fingers before the tubesheet is installed and remain in place thereafter to be removed and reinstalled as an assembly with the tubesheet at successive dismantling and reassembling.

The breakdown tube clamping and tube positioning bafile provides another novel feature in that it clamps the tube in a fixed position in the bundle and therefore eliminates the costly manufacturing of the precision constructed tube and O-ring retainer plates.

FIG. I is a longitudinal plan view partly sectional of a Floating Head type heat exchanger bundle.

FIG. II is a cross section of FIG. I taken through section line 2-2 at the face of a breakdown tube damping and tube positioning bafile assembly.

FIG. III is a longitudinal plan view partly sectional of a U bend type heat exchanger bundle.

FIG. IV is a cross sectional view of FIG. III taken through section line 44 at the face of the breakdown tube clamping and tube positioning assembly where it is attached to the inside face of a tubesheet.

FIG. V is a side view partly sectional of another adaptation of the breakdown tube clamping and tube positioning assembly for securing the U tubes and O-ring seal elements in the tubesheets of U bend or Floating Head type bundles.

FIG. V1 is a sectional view taken through section line 66 in FIG. V.

Referring to the drawings of FIG. I and FIG. II a tube bundle is shown having tubes 3 extending between tube sheets 10 axially spaced by stay rod 9. The tubes are clamped in position by a pair of assemblies 24. Each breakdown tube clamping and tube positioning baffle assembly 24 is comprised of segments 1 having semicircular shaped recesses 2 spaced along two of the opposite sides of each segment 1, except the two end segments 25 and 26 which have the recesses only on one side. These recesses 2 are near the same diametrical dimension as the outside diameter of the tubes 3 and they form close fitting holes through which the tubes 3 extend when the segments 1 are secured in place, with the sides having the recesses 2 juxtaposed to one another, by the baflle segments clamping element 4. The baflle segments clamping element is adapted to extend through a tube lane, transverse to the longitudinal axes of the segments 1, and is comprised of prongs 28 that form a crotched slot to receive all the segments 1 juxtaposed in the slot substantially as described to form one breakdown tube clamping and tube positioning bafile assembly 24.

The prongs 28 have threaded ends 5 that extend through holes 6 in the plates 7 that are attached to the opposite faces of the outermost segment 26 of the said baffle plate. The nuts 8 are provided for the threaded ends 5 and when tightened cause the segments 1 to be drawn perpendicular to the longitudinal axes of the tubes 3. The widest dimension of the segment 1 parallel with the slot and perpendicular to the tube 3 is such so as to cause the juxtaposed semi-circular shaped recesses 2, when drawn together, to contact and clamp the tubes 3 and prevent them from moving longitudinally through the tubesheets when the breakdown tube clamping and tube positioning baffie assembly is secured in a fixed position in the exchanger bundle by the stay rod 9 having reduced diameter sections extending through the recesses in end segment 25 and the segment 1 adjacent thereto as shown in the cut-away portion of FIGURE 1. The stay rod 9 also secures the tubesheets 10 at each end of the bundle in a fixed position when the nuts 11 are tightened into place on the threaded ends of the stay rod 9.

Circular grooves 12 are provided in the tubesheets 10 concentric with the tube holes 13 to receive and completely confine O-ring fluid pressure seal elements 14 around the tubes 3 extending therethrough. The O- ring seal element 14 is provided to prevent the mixing of the fluid under pressure on the tube side of the heat exchanger unit with the fluid on the shell side of the heat exchanger unit when the preponderance of pressure is in either direction. The breakdown tube clamping and tube positioning baffie assembly clamps the tubes 3 in such a manner so as to prevent them from moving out of the tubesheets 10 or from the O-ring elements 14 but they do have free thermal expansion or contraction throughout their entire lengths on either side of the breakdown baffle that does the clamping.

The bundle is disassembled for individual tube cleaning by removing the nuts 11 from the stay rod 9. This allows the tubesheet 10 with the O-ring elements 14 to be pulled from each end of the tubes 3. Nuts 8 are removed from the threaded ends 5 of the prongs 28 on all the baffle assemblies and the outermost segments 25 and 26 of all the baffle assemblies are lifted exposing the top row of tubes 3 which also are lifted from the bundle. This exposes the next segments 1 to be lifted which exposes another row of tubes to be lifted from the bundle. The procedure is repeated until all of the tubes 3 and segments 1 have been removed from the bundle.

The bundle is reassembled by placing one tubesheet 10 in position and the end segments 25 in their respective positions. The tubes 3 are pushed through the bottom row of holes from the inside face of the tubesheet 10 far enough so that the other ends of the tubes 3 when laid in the segment 25, that is positioned to be juxtaposed to the inside face of the tubesheet 10 at the other end of the bundle, so that the tube ends are flush with the face of the said segments 25. The next segments 1 are laid in place and another row of tubes 3 are installed as described. The procedure is repeated until all of the tubes 3, segments 1 and 26 and stay rod 9 are in place. The outer tubesheet 10 is put in position over the protruding ends of the stay rod 9 and secured in a fixed position with the nuts 11. The tubes 3 are already aligned in axial position with the tube holes 13 by the breakdown tube clamping and tube positioning assembly juxtaposed to the tubesheet 10 so that the tubes 3 are pushed into position through the O-ring elements 14 in this tubesheet 10 by applying force on the tubes 3 where they protrude beyond the outer face of the tubesheet 10 at the other end of the bundle. The segment clamping elements 4 are installed on each bafi le plate assembly and the nuts 8 are tightened on the threaded ends 5 of the prongs 28 to cause the segments to clamp the tubes 3 and secure them in a fixed position in the exchanger bundle. The bundle is ready to be installed in the heat exchanger shell or casing.

FIG. III and FIG. IV show another adaptation of the breaktube clamping and tube positioning assembly that makes it possible to use the mechanical principle of the O-ring fiuid pressure seals in the tubesheet 10' of a U tube type bundle so that it can be broken down for individual tube cleaning and reassembling. In this embodiment the tube clamping and tube positioning assembly is juxtaposed with the inside face of the tubesheet 10 but it can be located on the outside face if desired. The tube clamping and tube positioning assembly consists of baffie segments 1 similar to those shown in FIG. I and FIG. II but they are secured in a position to clamp and fix the position of the U-shaped tubes 3' on the same axial center to center spacing as the holes 13 in the tubesheet 10 by only one segment clamping element 4 extending transverse to the longitudinal axes of the said segments. This segment clamping element 4' has threads 5 on each end which extend through holes 6' in the plates 7 that are attached perpendicular to the faces of the outermost segments 26 of the said tube clamping and tube positioning assembly. The nuts 8' when tightened cause the circular shaped recesses 2' to contact and clamp the tubes 3 substantially as previously described. The segment clamping element 4' has an element 15 attached perpendicular to its longitudinal axis. The element 15 is threaded on the end and it extends through a hole formed in the breakdown tube clamping and tube positioning assembly and through a hole in the tubesheet to receive nut 11 which when tightened secures the tube clamping and tube positioning assembly to the tubesheet 10 thereby securing the U tubes 3 in a fixed position in the heat exchanger bundle.

The baffle tie rods 16 and spacer sleeves 17 are provided connected to an assembly of bafiie segments 18 through each row of tubes extend in a fixed position with respect to the tubesheet 10'. This tube bundle is disassembled by removing the nut 11' and pulling the tubesheet 10 from the ends of the tubes 3'. The nuts 8' are removed from the segment clamping element 4. The baflie tie rods 16' are unscrewed and removed with the spacer sleeves 17. The top tube clamping and tube positioning segment 1 is lifted and then a complete row of U tubes 3 with a bafile segment 18 is lifted from the bundle. The next exposed segment 1' is lifted exposing another row of U tubes 3' with bafiie segments 18 to be lifted from the bundle. This procedure is repeated until all the rows of U tubes and segments 18 are removed from the bundle. The bundle is reassembled by reversing this procedure. The tubesheet 10 is forced over the ends of the U tubes 3' by installing and tightening the nuts 11' once the tubes 3' are clamped and positioned by the breakdown tube clamping and tube positioning assembly comprised of segments 1.

Referring to FIG. V and FIG. VI another adaptation of the breakdown assembly is comprised of segments 18 in combination with an upset ring or collar secured to the outside of the U tube 3' near its end and a counterbore 21 from the inside face of the tubesheet 10' that is concentric with the tube hole 13. This counterbore 21 is adapted to completely confine the upset ring 20 and the O-ring fluid pressure seal element 14 around the tube 3 between the end of the upset ring 20 and the bottom of the counterbore 21. The breakdown baffle assembly comprised of segments 18' is secured to the tubesheet 10' in the same manner as the assembly shown in FIG. III and FIG. IV so that it abuts the end of the upset ring 20 in the counterbore 21 thereby securing the tubes 3 in a fixed position through the O-ring element 14 in the tubesheet 10 but does allow free longitudinal thermal expansion or contraction of the tubes 3' on either side of the said tube positioning assembly. This type of assembly is suitable in the same manner as the assembly shown in FIG. III and FIG. IV for lifting a complete row of tubes 3 at a time from the bundle and retain them as a complete row for cleaning. The tubes 3 are cleaned and reinstalled as a complete row of tubes. This type of assembly can also be used in the bundles with tubesheets at both ends. The segment 1 in FIG. I and FIG. II can also be used with the upset ring 20 and the counterbore 21.

It is obvious that minor changes in details of construction can be made without departing from the spirit of my invention.

Having fully described my invention and its mode of operation, I claim:

1. In combination with a tube bundle for heat exchangers having a longitudinal axis and including a tube plate perpendicular to said longitudinal axis and a plurality of rows of tubes extending through the tube plate parallel to said longitudinal axis, a battle assembly and means axially spacing said batfie assembly from the tube plate along said longitudinal axis, wherein the improvement resides in the baffle assembly which comprises a plurality of assembled plate segments including two and segments through which said rows of tubes extend, means extending transverse to said rows of tubes for holding the plate segments in assembled relation and clamp means interconnecting at least one of the end segments with the transversely extending means for locking the tubes against axial displacement relative to the tube plate, said axial spacing means being connnected to said plate segments for holding the baffle assembly in an axially fixed position.

2. The combination of claim 1 wherein each of said plate segments is provided with spaced recesses receiving one of said rows of tubes, each of said rows of tubes being clamped between the spaced recesses of adjacent plate segments.

3. The combination of claim 2 wherein said batfie assembly further includes a second plate formed from a plurality of assembled segments through which said rows of tubes extend, and means fixedly spacing the second plate from the two end segments aforementioned.

4. The combination of claim 3 wherein each of the segments of the second plate is provided with spaced openings through which one of the rows of tubes extends, whereby the tubes in each row of tubes may be simultaneously removed from the bundle upon disassembly of the bat'fie assembly.

5. The combination of claim 1 wherein each of the plate segments is provided with spaced openings through which one of the rows of tubes extends, whereby each row of tubes may be simultaneously removed from the bundle upon disassembly of the baflle assembly, and collars secured to each of the tubes between the batfie assembly and the tube plate.

6. The combination of claim 1 wherein said transversely extending means comprises interconnected bar elements forming a slot receiving the plate segments, said clamping means connecting the bar elements to one of the end segments, said axial spacing means being connected to the segments intermediate said opposite ends of the bar elements.

7. The combination of claim 6 wherein each of said plate segments is provided with spaced recesses receiving one of said rows of tubes, each of said rows of tubes being clamped between the spaced recesses of adjacent plate segments.

8. The combination of claim 7 wherein said baflle assembly further includes a second plate formed from a plurality of assembled segments through which said rows of tubes extend, and means fixedly spacing the second plate from the two end segments aforementioned.

9. The combination of claim 8 wherein each of the segments of the second plate is provided with spaced openings through which one of the rows of tubes extends, whereby the tubes in each row of tubes may be simultaneously removed from the bundle upon disassembly of the baflie assembly.

10. The combination of claim 6 wherein each of the plate segments is provided with spaced openings through which one of the rows of tubes extends, whereby the tubes in each row of tubes may be simultaneously removed from the bundle upon disassembly of the baffle assembly, and collars secured to each of the tubes between the bafiie assembly and the tube plate.

11. The combination of claim 1 wherein said transversely extending means comprises a folded bar element forming a slot receiving the plate segments, said axial spacing means being connected to the segments at an end of the bar element opposite the end to which the clamp means is connected.

References Cited UNITED STATES PATENTS 596,874 1/1898 Hand -159 1,704,097 3/1929 Muhleisen 165-162 X 1,738,848 12/1929 Starr 165-162 2,143,157 1/1939 Kotzebue l65162 X 2,969,956 1/1961 Forgo 165-162 X FOREIGN PATENTS 418,770 10/1910 France.

ROBERT A. OLEARY, Primary Examiner. A. W. DAVIS, Assistant Examiner. 

1. IN COMBINATION WITH A TUBE BUNDLE FOR HEAT EXCHANGERS HAVING A LONGITUDINAL AXIS AND INCLUDING A TUBE PLATE PERPENDICULAR TO SAID LONGITUDINAL AXIS AND A PLURALITY OF ROWS OF TUBES EXTENDING THROUGH THE TUBE PLATE PARALLEL TO SAID LONGITUDINAL AXIS, A BAFFLE ASSEMBLY AND MEANS AXIALLY SPACING SAID BAFFLE ASSEMBLY FROM THE TUBE PLATE ALONG SAID LONGITUDINAL AXIS, WHEREIN THE IMPROVEMENT RESIDES IN THE BAFFLE ASSEMBLY WHICH COMPRISES A PLURALITY OF ASSEMBLED PLATE SEGMENTS INCLUDING TWO END SEGMENTS THROUGH WHICH SAID ROWS OF TUBES EXTEND, MEANS EXTENDING TRANSVERSE TO SAID ROWS OF TUBES FOR HOLDING THE PLATE SEGMENTS IN ASSEMBLED RELATION AND CLAMP MEANS INTERCONNETING AT LEAST ONE OF THE END SEGMENTS WITH THE TRANSVERSELY EXTENDING MEANS FOR LOCKING THE TUBES AGAINST AXIAL DISPLACEMENT RELATIVE TO THE TUBE PLATE, SAID AXIAL SPACING MEANS BEING CONNECTED TO SAID PLATE SEGMENTS FOR HOLDING THE BAFFLE ASSEMBLY IN AN AXIALLY FIXED POSITION. 